This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. In a previous genome-wide scan, we identified BANK1 as a gene involved in susceptibility for SLE. Follow-up studies identified two polymorphisms in BANK1 that are specifically associated with SLE risk and which have an impact on the function and expression of BANK1 isoforms. We will work to test the hypothesis that the risk isoforms cause increased autoantibody production through disruption of molecular signaling cascades. B cells will be stratified according to their activation status and BANK1 expression levels will be tested in these subsets to identify any correlations.